[llvm] [RISCV][VLOpt] Move OperandInfo into anonymous namespace. Move getEMULEqualsEEWDivSEWTimesLMUL out of RISCVVType namespace. NFC (PR #125138)

[Michael Maitland via llvm-commits]

michaelmaitland wrote:

> LGTM.
> 
> Was it originally like this because we wanted to share it with RISCVVectorPeephole? Not sure if we still need to anymore.

We moved these functions into RISCVVType in case we shared it, but we did not end up doing that.

https://github.com/llvm/llvm-project/pull/125138